Codemasters Online has opened a new world server for RF Online called Solus. It seems that ever since the game has gone free to play, the popularity of the game has overpopulated the other two worlds, Novus and Lumen. Lumen was also opened within the last 30 days, so they are trying to respond to the increased popularity of the game as quickly as possible.
The game is gorgeous and fun, particularly for a free game. I have yet to play very long, however, because their European downtimes have unfortunately coincided with my U.S. available playtimes.
If you are interested in trying RF Online, you can sign up for and download your free copy here. Codemasters highly recommends starting new characters on Solus in order to avoid any population related issues.
Now, if I can just figure out how to turn off that song in the launcher...